Safety of peripheral intravenous administration of vasoactive medication

BACKGROUND

Central venous access is commonly performed to administer vasoactive medication. The administration of vasoactive medication via peripheral intravenous access is a potential method of reducing the need for central venous access. The aim of this study was to evaluate the safety of vasoactive medication administered through peripheral intravenous access.

METHODS

Over a 20-month period starting in September 2012, we monitored the use of vasoactive medication via peripheral intravenous access in an 18-bed medical intensive care unit. Norepinephrine, dopamine, and phenylephrine were all approved for use through peripheral intravenous access.

RESULTS

A total of 734 patients (age 72 ± 15 years, male/female 398/336, SAPS II score 75 ± 15) received vasoactive medication via peripheral intravenous access 783 times. Vasoactive medication used was norepinephrine (n = 506), dopamine (n = 101), and phenylephrine (n = 176). The duration of vasoactive medication via peripheral intravenous access was 49 ± 22 hours. Extravasation of the peripheral intravenous access during administration of vasoactive medication occurred in 19 patients (2%) without any tissue injury following treatment, with local phentolamine injection and application of local nitroglycerin paste. There were 95 patients (13%) receiving vasoactive medication through peripheral intravenous access who eventually required central intravenous access.

CONCLUSIONS

Administration of norepinephrine, dopamine, or phenylephrine by peripheral intravenous access was feasible and safe in this single-center medical intensive care unit. Extravasation from the peripheral intravenous line was uncommon, and phentolamine with nitroglycerin paste were effective in preventing local ischemic injury. Clinicians should not regard the use of vasoactive medication is an automatic indication for central venous access.

Potential role of endogenous adenosine in ticagrelor-induced dyspnea

Ticagrelor, a recently approved platelet antagonist indicated for the reduction of thrombotic cardiovascular events in patients with acute coronary syndrome (ACS), has been reported to cause dyspnea in more than 13% of patients. Dyspnea is not a clinically relevant adverse event with other medications indicated for ACS. One suggested mechanism of ticagrelor-induced dyspnea involves an increase in systemic adenosine concentrations through adenosine deaminase inhibition. Dyspnea, a subjective finding resulting from physiologic and sensory mechanisms, may be a consequence of increased systemic adenosine concentrations, leading to amplified and prolonged receptor activity. Current literature suggests, however, that pulmonary status is not compromised, with no reduction of efficacy seen in patients with ticagrelor-induced dyspnea, thus allowing clinicians to continue therapy without reservation. Still, patients with a history of asthma and chronic obstructive pulmonary disease may be more susceptible to ticagrelor-induced dyspnea, potentially leading to nonadherence and exacerbations of morbidity. Therefore, it is paramount that health care providers continually monitor these patients with the aims of maintaining medication therapy adherence and providing relevant options if dyspnea becomes intolerable.

Heparin management in a patient with thyroid storm

Management of atrial fibrillation during thyroid storm includes anticoagulation for risk of clot propagation. Physiologic changes that occur in patients with thyroid storm may lead to heparin resistance and inappropriate anticoagulation. Factors contributing to heparin resistance include antithrombin deficiency, increased heparin clearance, and increased levels of factor VIII. We describe a 30-year-old woman who was hospitalized with thyroid storm. She subsequently developed atrial fibrillation, and unfractionated heparin was started. Over the next 4 days, the heparin infusion rate was titrated to an exaggerated dose of 2100 units/hour (33 units/kg/hr) in order to attain a therapeutic response. By hospital day 7, her atrial fibrillation had resolved; the heparin infusion was discontinued, and the patient remained clinically stable with no sequelae. The exact mechanism of heparin resistance in thyroid storm is unknown; however, data have shown a positive correlation between factor VIII and thyroxine levels. This patient had an elevated thyroxine level of 32.5 microg/dl, which suggested that an increased factor VIII level was the probable mechanism of heparin resistance. Recognition of possible heparin resistance in patients with thyroid storm will allow clinicians to promptly identify appropriate interventions to ensure adequate anticoagulation in this high-risk patient population.